High performance relays are utilized in great numbers in the aircraft, aerospace, and electronics industries in which a premium is placed on minimum weight and physical size for operation under extreme environmental conditions and with high electrical capacities. Relays capable of switching currents of 10 amperes or more at switching times of less than a millisecond and occupying a total volume of less than seven cubic centimeters make the design and manufacture of the relay parts extremely critical and expensive. In attempting to scale down the size of component parts to reduce the weight and size of the relay, careful attention must be given to strengths of materials in order to withstand shocks of up to 200 g's, vibrations of up to 50 g's, and at the same time the relay must provide minimum contact resistance, as well as sufficient insulation and spacing to prevent voltage breakdown and arcing.
Such high performance relays are constructed so that the entire relay assembly, including the relay motor and the switches operated by the relay motor, are hermetically sealed. All the electrical connections to the switch contacts as well as to the electromagnetic motor are made through a group of connector pins which pass through a header, the pins being mounted in the header by glass or ceramic seals.
One arrangement for providing electrical connection between a contact pin and the moving switch contacts of the relay is shown in U.S. Pat. No. 3,484,729. This patent discloses an arrangement in which a bracket welded to the end of the contact pin extends parallel to a pivotally supported blade to which the moving contacts are attached. A flat spring formed in a compressed U-shape is positioned between the bracket and the blade, the ends of the U-shaped spring being bent outwardly to pivotally engage respectively the bracket and the center of the blade. The spring action holds the U-shaped contact spring in place with a minimum of load restricting the motion of the blade by the relay.
While the U-shaped spring as a separate part provides a satisfactory electrical connection, and retains itself in place by compression with a minimum of mechanical movement and drag, because it is a separate part it must be inserted after the relay is assembled. This is not only time consuming but takes considerable dexterity in the very tight spaces of a multipole relay.